The use of optical indicia, such as bar code symbols, for product and article identification is well known in the art. Decodable indicia reading terminals are available in multiple varieties. For example, minimally featured bar code reading terminals devoid of a keyboard and display are common in point of sale applications. Decodable indicia reading terminals devoid of a keyboard and display are available in the recognizable gun style form factor having a handle and trigger button (trigger) that can be actuated by an index finger. Decodable indicia reading terminals having keyboards and displays are also available. Keyboards and display equipped decodable indicia reading terminals are commonly used in shipping and warehouse applications, and are available in form factors incorporating a display and keyboard. In a keyboard and display equipped decodable indicia reading terminal, a trigger button for actuating the output of decoded messages is typically provided in such locations as to enable actuation by a thumb of an operator. Keyboard and display equipped decodable indicia reading terminals are available in a form in which the keyboard and display are commonly provided by a display having an associated touch panel. Decodable indicia reading terminals in a form devoid of a keyboard and display or in a keyboard and display equipped form are commonly used in a variety of data collection applications including point of sale applications, shipping applications, warehousing applications, security check point applications, and patient care applications. Decodable indicia reading terminals are also available in a presentation reader form factor. Such terminals can be mounted at a checkout station. Some bar code reading terminals are adapted to read bar code symbols including one or more of one-dimensional (1D) bar codes, and two-dimensional (2D) bar codes.
One common type of scan engine found in hand-held and retail scanners is the digital imager, which includes 1D (linear) imagers and 2D (area) imagers. Digital imagers typically utilize a lens to focus the image of the bar code onto a multiple pixel image sensor, which often is provided by a CMOS-based or CCD-based image sensor that converts light signals into electric signals. A light source such as light emitting diodes (LEDs) simultaneously illuminate all of the bars and spaces of a bar code symbol in order to capture an image for recognition and decoding purposes.